Lights are used in the horticultural field for a variety of purposes. For example, they are used to force seed growth during in climate months for later outdoor planting; in green houses to grow and maintain plants indoors, and, for certain agricultural crops that are grown indoors, such as mushrooms.
Lighting systems used to promote plant growth come in a variety of shapes, sizes, and types. Until the present invention, horticultural lighting systems have suffered from the same shortcoming: while providing adequate light for plant growth, they generate significant heat. Depending on the distance the light is mounted from the plant, the heat reaching the plant may exceed 100.degree. F. Heat may be acceptable for some plants but others are effected negatively by the heat generated by the lights. Deleterious effects such as delicate new growth leaf burning and excessive soil drying can result. These effects, in turn, lead to unnecessary plant loss, thereby decreasing harvest potential and increasing costs.
The prior art is replete with horticultural lights. The devices, however, principally focus on illumination. See, for example, U.S. Pat. Nos. 4,078,169, 4,600,973, 4,609,974, 5,025,356, and 5,065,294. Certain attempts have also been made to reduce or eliminate the problems associated with excessive heat. However, these attempts have been limited to heat reduction for infrared lights and stage lights, and are not suitable for use in horticultural settings.
U.S. Pat. No. 4,321,659 to Wheeler discloses and claims a narrow band, air-cooled light fixture. The device is designed to filter conventional broad spectrum energy so that only desired spectrum regions are transmitted. The device employs a fan and series of filters containing a plurality of holes to emit light to achieve its stated purpose.
A variation of U.S. Pat. No. 4,321,659 is seen in U.S. Pat. No. 4,546,420 to Wheeler, et al, which discloses and claims a similar device having the same stated purposes but instead of filters containing a plurality of holes, this version employs filters having slotted peripheries.
There is a need, therefore, for a horticultural light apparatus that promotes growth through adequate supply of light yet generates little heat, thereby reducing damage to heat sensitive plants. Such a system should be simple to use and not add significantly to the cost of artificial light based horticulture.